Thanks so much for lending your expertise Tatsuo. Aviel I have found and linked below the relevant section of the official pgpool-II docs on using pgpool-II for failover. It is available starting in pgpool-II version 3.1: http://www.pgpool.net/docs/latest/pgpool-en.html#stream
*Will J. Dunn* On Tue, Jul 21, 2015 at 10:07 PM, Tatsuo Ishii <is...@postgresql.org> wrote: > > But it appears that the fail condition for "watchdog" is the failure of a > > pgpool-II instance. In the configuration described in the wiki you would > > put a pgpool-II instance on each Postgres node, and if one of the > pgpool-II > > instances fails it executes a script (which can create the trigger file > to > > promote the standby to master). However, if the fail condition for > watchdog > > is a failure of the pgpool-II instance what happens if the DBMS has > > availability issues but the pgpool-II process on that server is ok? The > > fail condition would never be triggered, right? > > No. The condition (PostgreSQL failure) will be detected by one of > pgpool-II (not watchdog process) and the pgpool-II will disconnect the > failed PostgreSQL, then execute failover script (if defined) which > will usually promote standby PostgreSQL (if failed PostgreSQL was > primary) or just ignore the broken PostgreSQL if it was standby. > > Best regards, > -- > Tatsuo Ishii > SRA OSS, Inc. Japan > English: http://www.sraoss.co.jp/index_en.php > Japanese:http://www.sraoss.co.jp > > > *Will J. Dunn* > > *willjdunn.com <http://willjdunn.com>* > > > > On Tue, Jul 21, 2015 at 4:27 PM, Joshua D. Drake <j...@commandprompt.com> > > wrote: > > > >> > >> On 07/21/2015 01:21 PM, William Dunn wrote: > >> > >>> That's pretty cool! But the intended use of watchdog is so you can have > >>> multiple pgpool-II instances and failover among them > >>> (http://www.pgpool.net/docs/latest/pgpool-en.html#watchdog) rather > than > >>> failure of Postgres. In the configuration described in that wiki what > >>> happens when the DBMS goes down but pgpool-II is fine? The watchdog > >>> appears to be monitoring the pgpool-II process, not the > >>> postgres/postmaster process. > >>> > >> > >> From what I see, it has the ability to execute a command/script based > on a > >> failed condition which could include but not be limited to a command to > >> fail over a standby. > >> > >> > >> JD > >> > >> -- > >> Command Prompt, Inc. - http://www.commandprompt.com/ 503-667-4564 > >> PostgreSQL Centered full stack support, consulting and development. > >> Announcing "I'm offended" is basically telling the world you can't > >> control your own emotions, so everyone else should do it for you. > >> >
